Method of applying braking force to hoisting drums



NOW 1952 R. R. CROOKSTON METHOD OF APPLYING BRAKING FORCE YO HOISTING DRUMS Filed Aug. 50, 1946 2 SHEETSSHEET l yd mvsm'oa Nov. 25, 1952 R. R. CROOKSTON METHOD OF APPLYING BRAKING FORCE TO HOISTING DRUMS Filed Aug. so, 1946 2 SHEETSSHEET 2 FIG. 3'.

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ATTORNEY.

Patented Nov. 25, 1952 METHOD OF APPLYING BRAKING FORCE T HOISTIN G DRUMS Robert R. Crookston, Houston, Tex., assignor,

by mesne assignments, to Standard Oil Development Company, Elizabeth, N. J., a corporation of Delaware Application August 30, 1946, Serial No. 693,993

4 Claims. (Cl. 188-105) The present invention is directed to a method for applying a braking force to a hoisting drum. More specifically, the invention is directed to the application of a braking force to a hoisting drum involving the application of braking forces through at least one frictional surface.

The use of hoisting devices is well known to the art. In the operation of such devices, it is often necessary or desirable to control the rotation of the hoisting drum under a load. The conventional method for controlling such rotation is by the application of a braking force through a braking band havin a lining in frictional contact with a surface of the hoisting drum. Inasmuch as the loads carried by the hoisting drum may be very large, the total forces involved in controlling the rotation of the drum are also large. Although large forces are involved it is frequently desirable or necessary to control the rotation of the drum as it rotates under load accurately, that is to say, it is often necessary or desirable either to control the speed of rotation accurately or to control the point or points at which the drum is stopped accurately.

An example of the use of a hoisting drum where the drum rotates under a, heavy load and its rotation must be controlled accurately is in the conventional drilling of deep boreholes with the rotary drilling method. In this operation the hole is drilled by rotating a drill stem carrying a drill bit on its lower end and in order to produce a strai ht hole as well as to employ the equipment efficiently, it is necessary to lower the drill stem at such a rate so as to keep a substantially constant load on the drilling bit. In the drilling operation a draw works including a hoisting drum carries a cable which passes through crown blocks mounted on the upper end of the derrick with a travelling block supported from the crown block by the drilling line and as each new joint of pipe is added to the drill stem a part of the weight is taken by the drilling line and as the hole is deepened the drilling line is paid out from the hoisting drum until the hole is deepened a length equal to the joint of added pipe at which time another joint of pipe is added to the drill stem, a part of the weight supported by the drilling line and the remainder allowed to rest on the drill bit and the drill stem rotated to continue the drilling operation.

It is an object of the present invention to devise a method for controlling the rotation of a hoisting load which allows the speed of rotation tobe controlled more accurately than heretofore possible.

2 It is another object of the present invention to control the rate of rotation of a hoisting-drum with a small amount of manual effort by the operator of the hoisting drum.

Other objects and advantages of the present invention will be seen from the following description.

The method of the present invention may be described briefly as involving the application of a major brakin force to a hoisting drum through a frictional lining and superimposing on the major braking force a minor braking force which taken with the major braking force completely controls the rotation of the drum. In accordance with the present invention, the rotation of a hoisting drum is controlled by applying a major braking force and an additional minor braking force which is only a small fraction of the major braking force with the major braking force applied at a substantially uniform rate and the control of the drum obtained by varying the application of the minor braking force.

The method of the present invention involves the employment of a combination of major and minor forces which makes it possible to control the speed of rotation, or payoff in the case of oil well rotarydrilling rigs to a closer degree than would be possible when employing a major force alone, and at the same time permits that the controlling be done with a minor effort on the part of the operator as well as the device doing the controlling.

In its more specific aspects several different procedures may be employed for carrying out the present invention. For example, a large frictional surface, such as a conventional brake band, may be employed for applying the major braking force and an auxiliary braking surface of smaller area may be used for applying the minor braking force. As another method of practicing the present invention the major braking force may be applied through a frictional surface, such as a conventional brake band, by applying a 'fixed tension on the brake band and exerting on the brake band a minor force which is varied to control accurately the rotation of the brake drum. As an example of such a procedure, a brake band controlled by. a hand operated lever may have a uniform tension exerted through the lever on the brake band as by attaching the lever by a chain to a fixed point and a small force added to the major force as by an operator attaching a light line 'to the center of the chain and exerting a pull at right angles to the axis of the chain. As ane other example, a brake operated by a conventional end lever may have the lever attached to a fixed point, as by a chain, to exert a major braking force and a minor braking force added to the system by imposing on a small area of the brake band a force to press it against the brake drum, as by the use of a lever, such as a pry bar, resting on .a fulcrum with the operator exerting a force against one end of the bar and the other end of the bar pressing against an area of the brake band.

The present invention will now be described in greater detail in conjunction with the drawing in which:

Fig. 1 is an elevation, partly in section, illustrating one arrangement suitable for use'in the practice of the present invention;

Fig. 2 is a top view of another embodiment suitable for use in the practice of the present invention;

Fig. 3 is a view taken along line IIIIII of 4.is a fragmentaryview showing the details of construction of a portion :of the device of Figs. 2 and 3; and

Fig. is an elevation, partly in section, of another arrangement suitable for use in the-practice of the present invention.

Turning now specifically to the drawing and first .to'Fig. 1, a hoisting drum 'II is mounted for rotation about'an axis I2 on a frame the base plate of which is shown at I3. A wire line I4 is carried .by the drum. Brake band I'5, provided with ifriotion lining l6,-is mounted on the drum whereby contraction of the brake band engages the friction lining with the brake drum and holds the-drum against rotation.

Means-are providedfor contracting brake band I5 wherebythe major portion of force required to 'control' the rotation of the drum may be exertedrand an independent means is provided for exerting'a -minor force upon the brake drum which coupled'with the aforesaid major force, completely controls therotation of the drum as it :is rotated under the' tension exerted by any suitable load on line I4.

' Themeans for applying the maior force to the brake :band includes a power unit with cylinder II, piston I8 arranged to reciprocate thereinand piston rod It with oneend attached to piston 18 and projecting through the piston rod end of cylinder H. The cylinder is mounted on trunnions 2D and plates 2| carried by brake band member I5. The free e d of the piston rod I5 isfi'tstened. through pin 22 to link 23 which has its other end fastened to brake band I5 by pin 24. Lever -23-ispierced to'receive a pin 25 which serves to attach an end-"of link 25 to link 23. Link is attached through pin 21 to clevis 28 which, in turn, is secured to brake band I5 through pin 29. Pin 21 also serves to attach clevis-28-and link 26 to link 30 which, in turn, is secured to-brake band 15 through pin 3|. An end f brakeband I5 adjacent link 30 isprovided with-a projection 32 which is secured to rod 33 by pin 34; the other end of rod 33 is attached to-base member I3 by pin 35. It will be seen that rod 33serves as a hold-down member for brake band I5. A compressed fluid, such-as air, may be supplied to the piston rod end of cylinder I! by line 36, which may be-controlled by any suitable valve means, not shown, and similarly a'compressiblefluid maybe supplied to the head end of the cylinder through conduit 3! which may also-be controlled by valve means, not shown. Theassenibly of Fig. 1 is provided with means for applying a braking force over a minor area. The means includes a rod 38 secured by pin 39 to projection '40 attached to brake band I5 by suitable means, such as welding, not shown. A housing, consisting of a head member 4| and rod enclosing member 42 define flanges between which is mounted diaphragm member 43 which is attached to the rod 38 by a suitable means, not shown. It will be understood that the arrangement of the diaphragm and housing shown in the drawing is well known to the art for transforming energy supplied in the form of a compressible ,fluid into mechanical movement, as, for example, for ibe-operation of pneumatic brakes for freight trucks. A-compressible fluid may be supplied in the space defined'by the interior of housing 4| and diaphragm .43 by conduit 44 which may be provided with a suitable valve means, not shown.

"When utilizing the device of Fig. l for carrying out the present invention, a major braking force for controlling the-rotation .of hoisting drum H :isexerted through brake band I5 .and frictional surfaces IG-by a compressible fluid supplied through conduit 36 to the piston rod end of cylinder IT. A minor portion of the force, suficient inamount that-when cooperating with the major force it controls completely the rotation of the hoisting drum,,is exerted by a compressible fluid supplied through conduit 44 and exerted against-diaphragm 43. It will be understood that an operator will manipulate the apparatus so that a major portion of the force, for example, .of the order of per cent, will be exerted by means of piston .rod I9 to supply a tension to the brake .band l5 and the remaining energy will be applied to a localized area of the brake band through diaphragm 43 and rod 38. Bythe use of this system a Vernier or micrometer effect is obtained .with force exerted .on piston I8 maintained at a constant value and the rotation of the hoisting drum closely and accurately controlled by varyin the pressure exerted throughconduit 44 which, in turn, is transmitted through diaphragm 43 and rod 38 against a small area of brake band I5.

Another arrangement suitable for the practice of the present inventionis shown in the embodiment of Figs. 2, 3 and 4. The apparatus of this embodiment is described in detail and claimed in my copending application Number 691,485 entitled Braking Device, filed August 19, 1946, now Patent No. 2,589,059, issued March 11, 1952.

.In this embodiment .a hoisting drum .50 .is indicated by dashed lines inFig. v2 ,and is shown .in section inFig. 3. The drum is mountedfor rotation about -.an.axis 5I.,,indicated by dashed lines in Fig., 3 ,andis supported on frame .52. The drum is arranged to control vthe movement of wire rope orline I4. Power for applying arotary movement to the drum is supplied by belt 53, shown in Fig. 2, arranged to otatea pulley, not shown, mounted on shafti I.

Means for applying a major braking force to the brake drum is supplied throughbrake band assemblies A and A which are controlled by power assemblies B and B. Means for supplying a minor braking force to the brake drums are supplied by assemblies C and C arranged to be operated by power assembly D.

The brake assemblies A and A each include a brake band '54 provided with a friction lining 55. An end'of brake band 54 is secured to frame 52 by members 56 and 51 fastened together by pin'58. The other end :of brake band 55 isattached through a crank arm, not shown, to shaft.

59. Shaft 59 is secured to frame 52 by means of journals 60 whereby it is free to rotate about an axis parallel with the axis of shaft 5| supporting the hoisting drum. It will be obvious that angular movement of shaft 59 in one direction will cause brake bands 54 to be tightened on the brake drum, while movement in the opposite direction will release the brake bands from the brake drum. The means for supplying such angular motion to shaft 59 are supplied by power assemblies B and B.

' Each power assembly B and B includes a cylinder 6| with a piston 82 slidably arranged therein. Piston B2 is secured to a piston rod 63 which has an end attached through pin 8 2 to crank arm 65. The crank arm 65 is secured to shaft 55. Cylinders 8| are mounted to frame 52 by trunnions 66. Power for operating the pistons in the cylinders in power assemblies B and B is supplied by fluid which may be transmitted to the head end of cylinders 63 through inlet lines 6'! and to the piston rod ends of the cylinders through inlet lines 68. It will be apparent that upon supplying compressible fluid to the head ends of cylinders 54 the pistons 52 will be forced away from the head ends of the cylinders and, in turn, will rotate crank arm 65 and tighten the brake bands 52 on the brake drum. It will also be evident that the amount of friction applied to the brake drums may be regulated by regulating the pressure supplied to the head ends of cylinders 6!. In addition, when desired, the brake bands may be positively released from the brake drum by releasing pressure in lines 6? and supplying pressure to the piston rod ends of cylinders ti through inlet lines 63.

Each assembly C and includes a member defining a plane surface on which is mounted a fiat brake lining member it. A bent crank arm l! is mounted in journal '72 which, in turn, is supported by frame 52. The upper end of arm ll is provided with a pin l2 for linking member E59 therewith. The lower end of crank arm "I! is engaged with an end of rod it for movement therewith. Ihe adjacent ends of rods it are connected through links M to link :"5 which, in turn, is secured to piston rod it of power unit D. Power member D is made up of a housing including a head member T! and piston rod member '58 with a diaphragm "is having its edges secured between the two housing members and said diaphragm secured to piston rod it by a suitable means, not shown. Means for supplying fluid into the space defined by housing memher 1? and diaphragm is is provided by conduit 83.

It will be seen that the assemblies C and C and power assembly D enables a braking force to be applied to the braking drum. Upon supplying compressed fluid through conduit 89 to exert pressure against diaphragm '59, the piston rod 16 is moved away from head end member '5? of the housing and, in turn, forces friction members against the radial surfaces defined by the hoisting drum 58. The amount of force exerted through surfaces Tl may be regulated by the pressure exerted against diaphragm 79; if it is desired to release braking surfaces '10 this may be done by releasing the pressure from conduit 80 whereby the elasticity of the diaphragm is sufficient to retract friction lining members it from contact with the brake drum.

The means for controlling the pressure of the compressed fluid supplied to lines 6?, 63 and 80 may be regulated by any conventional control means. Suitable valve arrangements for controlling the pressure in these lines is described and shown in detail in my copending application entitled Braking Device, mentioned heretofore.

When utilizing the device of Figs. 2, 3 and 4 in accordance with the present invention the line M may be paid off at the desired rate by supplying compressed fluid to power elements B and B at a substantially constant rate to exert a major portion of the friction force through friction lining members 55; for example, it usually will be found desirable to exert approximately per cent of the total braking force through the brake band assemblies A and A. The remainder of the desired braking force may be exerted through assemblies C and C and may be adjusted quickly and readily by altering the pressure of the fluid supplied to power unit D. In this way the major braking force exerted may be maintained at a fixed amount and the additional braking force required to control closely the movement of the brake drum is exerted through assemblies C and C. This arrangement allows the same effect to be obtained as is obtained in the use of a Vernier scale in measuring instruments.

Another embodiment suitable for use in the practice of the present invention is shown in Fig. 5. In this figure hoisting drum BI is mounted for rotation on shaft 82, supported on frame 83. The speed of rotation of the hoisting drum, as by a force exerted on a wire line, not shown, carried by the drum is controlled by brake band 84 provided with frictional lining 85. One end of brake band 815 is secured to frame 83 through members 86 and 8'1, connected together with pin 88. The other end of brake band 84 is adapted to be moved for contraction or release of the brake band with respect to the hoisting drum and in the drawing the means are shown as including a shaft 89, a crank arm 9i) secured thereto and attached to the end of the brake band by pin 9|. A hand lever 82 is secured to shaft 89 for movement therewith.

When using the embodiment of Fig. 5 in the practice of the present invention the lever 92 may be secured to the frame by chain 93 with a major portion of the desired braking force exerted through frictional lining B5 merely by the tension exerted through chain 953. For example, as heretofore explained, it will usually be desirable to exert approximately 95 per cent of the braking force by securing the end of lever 92 to frame 83 by means of chain 93. The additional increment of force required to control completely the rotary movement of hoisting drum 8| may be supplied by tying a rope 9 to the center portion of chain 93 and exerting a tension in the rope in the direction indicated on the drawing by an arrow and at right angles to the longitudinal axis of chain 93. Such a force may conveniently be exerted on rope 94 by an operator pulling on the rope. By the use of the embodiment of Fig. 5 an operator may control easily and accurately the movement of a hoisting drum and utilize in such a control much larger forces than is necessary for the operator to exert through rope 94.

While I have disclosed specific arrangements of apparatus suitable for use in the practice of the present invention, it is to be emphasized that the present invention is not limited to the use of any particular form of apparatus and that the forms of apparatus shown are given merely by way of suitable examples. It will be obvious to a workman skilled in the art that other arrangements may readily be employed in'the practice .of the present invention. While I have disclosed in the embodiment of Fig.1 and that of Figs. 2, 3 and .4 apparatus wherein major force is supplied through a power unit and the minor force supplied through another power unit, it will be apparent that, if desired, the major force may conveniently be supplied through a power unit andthe minor force .by manual effort. For eX- ample, the apparatus shown in Fig. 1 may be modified by supplying the minor force by means of a hand operated lever instead of compressed fluid. Similarly,in the embodiment of Fig. 2 the minorbraking effort may be supplied through a handoperatedunit in lieu of the power operated unit. v.It will also be apparent to a workman skilled in the'art that, if desired; the major effort may be supplied through manually operated means and the minor effect through a power operated means butin almost all instances it will be found advantageous to supply at least the major effort through a power means.

.It is to be understood that, while specific arrangements for practicing the present invention have been shown in detail, these arrangements may be modified as to sizes and proportions as well as in the modes of applying power to the frictional linings contacting the surfaces of the brake drum whose rotary movement is controlled by means of the force applied thereto and that it is my intention to embrace such variations within the hereto appended claims.

Having fully described and illustrated the practice of the present invention, what I desire to claim asnew and useful and to secure by Letters Patent is:

1. A method for controlling the speed of rotation of a rotating hoisting drum including the steps of continuously applying a major braking force through a frictional surface large enough substantially to control the said speed, independently of and concurrently with exerting continuously a minor braking force through a frictional surface in contact with the drum to control completely the speed'of rotation of said drum, said minor braking force being a small fraction of the total of said minor and major braking forces.

2. Amethod for controlling the speed of rotation of a'hoisting drum comprising the steps of continuously applying to the hoisting drum a major braking force through a frictional surface sufficient to equalize a major portion of the force rotating the drum, and concurrently with said major force continuously imposing on the hoisting drum through another frictional surface of small area a minor force no greater than a small fraction of the total force rotating the drum whereby the major and minor forces control completely the speed of rotation of said drum.

3. A method for controlling the speed of rotation of a rotating hoisting drum including the steps of continuously exerting on the rotating drum through a frictional surface a major braking force equal to a major portion of the total force rotating said drum, continuously imposing through a portion of said frictional surface a minor force consisting of only a small fraction of the total force rotating the drum concurrently with said major force, said minor force and major forces together completely controlling the speed of rotation of said drum.

4. A method for controlling the speed of rotation of a hoisting drum comprising the steps of continuously applying to the hoisting drum through a frictional surface a major braking force of sufficient magnitude to equalize a major portion of the force rotating the drum and concurrently with said major force, imposing on said drum through a frictional surface a minor braking force of sufficient magnitude to control completely the speed of rotation of said drum, said minor braking force being no more than 5% of the total of said major and minor braking forces.

ROBERT R. CROOKSTON.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 596,514 Ihlder Jan. 4, 1898 1,327,656 Drake et a1 Jan. 13, 1920 1,871,164 Dunlop Aug. 9, 1932 2,174,400 McCune Sept. 26, 1939 2,392,068 Sexton Jan. 1, 1946 

